Thanks for the info & for the link also.
I performed a quick search in the Europe market (via web) they are all out of stock in the SV811-3. Are you sure that 572-3 and 811-3 are equivalent types ?
costas
Yes, depending on what operating conditions you use. Will determine whether they can be interchanged or not the 572-3 can make more power but in doing so will eliminate the 811-3 the interchange ability.
But based on your operating conditions of your amp I see no issues, The 572 will give you a little more current capacity which yields a little more extension at the frequency extremes. But the 811 will be a bit warmer in the mids. I believe this is due to the 572's graphite plate vs the 811's metal plate. These tubes are cut from the same cloth as my 572-10 and 811-10 the 811-10 is much prettier to look at.
Oh Yeah, You won't have to use feedback with these!
My only other concern is the drive capability in your circuit for A2 it needs a low impedance drive to use either of these tubes to get the wattage from the 450-500volt B+.
Here's the pdf's
www.tubebuilder.com/images/tubedata/sv572-3specs.pdf -
www.g8wrb.org/data/Svetlana/pdf/SV811-3.pdf -
So were talking about 10-15 watt range in Class A2 for the 572-3 and 811-10
The differences in sound to be heard will be determined by the amps design and the rest of the systems capacity for being informative. Other than that the differences in my 10's was said to be not worth the expense. But in my system its very audible and I like both with the 572 being closer to neutrality and putting the foot to the floor when called upon.
Last I heard New Sensor had some 10,000 of these!
Myself I won't worry whether I could get them or not as there are a number of valves that could work with a 5k primary and the voltages run here.
Heres a 7 watter original version of my amp although mine substantially improved over this one but this one will give a taste of that big SET sound of the 845 or 211.
View attachment 118990
Up graded driver circuit for 10 watts
View attachment 118994
Here's what mine looked like when completed in 1998 pictured is one mono upright and one viewed from its bottom.
View attachment 118996
Next is a closer view of the circuit.
View attachment 118997
Next is my latest work to the amp which no longer really resembles what is in the schematic!
View attachment 118998
I built these amps to give what is referred to By Eric Barbour as the Big Transmitting tube sound! When they were completed I felt they accomplished his goal.
Through refinements I have managed to get the amplifiers to yield some of the most powerful sound that I have ever heard from 10 watts peak or just a mere 5.5 watts RMS.
I have learned through experience that a watt isn't just a watt!
In other words if the first one isn't great, don't expect 200 more to be great!
Through the yrs I have gone from 400 watts rms/channel to the mere 5 I have now yet the 5 are some of the most powerful I have ever owned.
Watt for watt these mono's have come across subjectively substantially with more dynamic weight than several high power SS amplifiers I have recently heard and some of them cost 10 times more in cost than what these cost me to build.
You will hear people talking about SET amps being wimpy! and many are!
I feel the wimpy SET amps that people talk about are just classical designs that fail to give involvement to many listeners.
The mono's I built have no classical implementation of design to them at all.
I also use no preamp. Just CD direct with its variable output. Preamps often just get in the way of what these mono's can do.
If you would like to know more I'd be happy to explain the circuit more and the associated gear that I use.
SET12
![JimJ[VT]](/forums/data/avatars/m/20/20031.jpg?1443894878){kind=avatar}
o you have any pictures of your amps and a schematic?
